Valve for levitated vehicle track

ABSTRACT

A pilot operated valve for use in combination with a track which supplies air for levitating a vehicle for movement along the track. The valve may be automatically actuated by pilot pressure built up underneath the vehicle, and is self-closing after the vehicle has passed. Pilot operation is provided to insure rapid and accurate operation, and also control pressure conduits can be provided for making the valve open in response to signals other than air pressure rise underneath a levitated vehicle.

United States Patent Bloomfield [54] VALVE FOR LEVITATED VEHICLE TRACK [72] Inventor: Roger D. Bloomfield, St. Louis Park,

Minn.

[73] Assignee: Uniflo Systems Company, Edina,

Minn.

22 Filed: May 15,1970

21 Appl.No.: 37,691

[52] US. Cl. ..251/28, 25l/6l.l, 104/134, 137/4542 [51] Int. Cl. ..A63g 21/00, F16k 31/365 [58] Field of Search ...251/28, 61.1, 45, 46; 137/487, 137/4542 [56] References Cited UNITED STATES PATENTS 10/1951 McPherson; ..251/6l.l x 11/1952 Graham ..25l/28X 1151 -3,685,788 1 51 Aug. 22, 1972 Rich..; ..137/487 2,877,791 3/1959 1,731,571 10/1929 Heare ..25 l/46 FOREIGN PATENTS OR APPLICATIONS 217,188 9/1961 Austria ..251/45 Primary Examiner-Arnold Rosenthal' Attorney-Bugger, Peterson, Johnson & Westman 57 ABSTRACT A pilot operated valve for use'in combination with a track which supplies air for levitating a vehicle for movement along the track. The valve may be auto matically actuated by pilot' pressure built up underneath the vehicle, and is self-closingjafter the vehicle has passed; Pilot operation is provided to insure rapid and accurate operation, and also control pressure conduits can be provided for making the valve open in response to signals other than air pressure rise underneath a levitated vehicle.

6 Clairm, 6 Drawing Figures VALVE FOR LEVITATED VEHICLE TRACK BACKGROUND OF THE INVENTION The advance of air levitated vehicles has brought l0 about various valve designs for operation therewith.

For example, in the patent to Flexman et al. U.S. Pat. No. 3,081,886, a pilot operated mechanically actuated valve is shown. The Flexman et al. valve senses pressure and operates a linkage through a large pilot diaphragm to open a valve to give levitation fluid underneath the vehicle.

. The patent to Bouladon et al. US. Pat. No. 3,279,863, also shows a different form of pilot operated valve for a levitated vehicle, wherein the valve itself is movable in the floor and opens ports to a conduit or plenum chamber used for the vehicle.

SUMNIARY OF THE INVENTION The present invention relates to a pressure-operated valve for air levitated vehicles which is pilot operated, and can be opened in response to fluid pressure under the levitated vehicle, or which may be actuated in response to a separate control pressure, as desired. The valve structure operates in a positive manner once the pilot actuating pressure is at the right level for operation, and utilizes relatively soft sealing diaphragms for FIG. 6 is a sectional view taken as online 6-6 in FIG. 5 with parts broken away to show a fluid passageway.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG 1 illustrates a fragmentary perspective view of a levitated vehicle track illustrated generally at 10 which has valve assemblies illustrated generally at 11 installed therein. The valve assemblies are made according to the present invention.-

The track 10 is made of a pair of oppositely disposed substantially parallel side walls 12, 12, a main support platform 13, and a bottom wall 14 that fonns a chamber 15.

As shown, the valves 11 are placed in two substantially parallel rows and in opposed pails transversely spaced across the floor 13. The valves 11 are inserted control portions of the valve will be in communication operation. The valve units are self-contained, and can.

be removed with a simple twist lock mechanism from the floor or track used for the levitated vehicle, and have a self-sealing connection to the respective control conduits or headers to make quick removal and replacement easy. The major portions of the valve can be simply molded from plastic materials, the diaphragms made of molded elastomeric materials, and very little machine work is necessary.

The pilot pressure sensing ports are self-cleaning upon actuating because a reverse puff of air is exhausted out through the pilot ports once the valve has been actuated to insure that any dirt that may have been injected into the pilot port or passageway would be blown clear. The valve operation is positive even with small differentials in pressure between the source of pressure and atmosphere.

A control diaphragm construction utilizing a sealing lip construction for obtaining a snap action type of seal for a passageway is also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS S.

FIG. 1 is a fragmentary perspective view of an air levitated vehicle and track showing a valve made according to the present invention installed therein:

FIG. 2 is a fragmentary top plan view of the valve device of the present invention;

FIG. 3 is a fragmentary enlarged sectional view taken as on line 33 in FIG. 2 and schematically showing a portion of an air levitated vehicle;

FIG. 4 is a view taken substantially as FIG. 3 but showing the valve in actuated or open position;

FIG. 5 is a side elevational view of the valve of the present invention shown installed in a vehicle track; and

with an opening 20 provided in the top wall 18 of the control pressure header. Control pressure conduits 21 and 22 are provided and these extend along the plenum chamber 15. The conduits 21 and 22 are connected to sources of fluid pressure used for control purposes. The conduits 21 and 22 are connected to the control pressure headers 17 so thatthe proper control pressure'will be available at each of the valves. One of the control pressure conduits opens to each of the chambers for providing control fluid pressure to each valve 11. If desired, the conduits may be used as separate headers and the valves would be connected to either one or the other of the conduits and grouped as desired.

A levitated vehicle illustrated generally at 24 has a primary load supporting platform 25, and can have end and side walls illustrated at 26 for holding a load to be conveyed along the track 10. For example, the levitated vehicle 24 could be used for carrying baggage in an airline terminal, or commodities in a warehouse where the levitated track is to be utilized. The platform 25 has a peripheral bag type seal illustrated generally at 27 around the peripheral edges thereof.

In the operation of the unit, the levitated vehicle is lifted with a cushion of fluid pressure greater than atmosphere underneath the platform 25, and the bottom edge of the seal 27 will just barely clear the surface of the wall 13. The vehicle will be moved along the track by properly directing the air coming through the valves 1 1 from the plenum chamber 15.

Each of the valves 11 comprises a main housing 30 which has a nozzle 31 defined therein. The nozzle 31 is directed at an angle with respect to the vertical, so that fluid, such as air, issuing from this nozzle'will tend to propel any vehicle 25 above the valve when it is opened in a direction along the track, for example the direction indicated by the arrow 32. The main housing 30 of the valve is provided with an overhanging shoulder 33 that fits over a peripheral support lip 34 offset downwardly from the floor 13. The inner peripheral edge of support lip 34 is serrated, as shown in FIG. 6, to have a plurality of lugs 35 and alternate open spaces. I

Spaced below the shoulder 33'of the valve body outwardly protruding bosses 36 are provided on the valve body. The bosses 36 are spaced around the periphery also shown in FIG. 6, and these bosses are made so that they will fit under the lugs 350. The entire valve assembly canthus be twist locked into place by inserting the valve into the opening defined by lip 34 so the bosses 36 go betweenadjacent lugs35, and then after the valve is inserted, twist locking the valve so bosses 36 areheld under lugs 35. A resilient gasket 37 pro- .vides for a resilient force which will hold the bosses 36 in engagement with the members 35 after they have been locked in place and also seals the openings into which the valves are placed. The upper surface of the valve ll 'is substantially coplanar with the surface of the floor or upper wall 133 The: nozzle 3l extends from and is open to a fluid passageway 40 that opens to the plenum chamber 15.

Flow through this passageway 40 andnozzle 31- is controlled by 'a flexible elastomeric diaphragm 41. One surface of .the diaphragm 41 defines a side of the fluid passageway 40. As shown, the housing'30 for the valve "is made into several sections, for assemblypurposes,

andthe diaphragm 41 is mounted over a valve block 42 a '(the diaphragm is cup shaped), and a second surface of the diaphragm rests against a contoured'upper surface 45 is open to the plenum chamber 150 A control diaphragm 46 is mounted on the opposite side of block 42 from surface 43, and is held in place with a retainer cap 47 that is swagged or bent over around the main portion of the valve block 42, holds blockv42 in place in the assembly and holds the entire valve assembly together, including a top member in which. the nozzle 31 is formed. The retainer cap 47 holds a very light spring 48 against a centering boss 49 on the diaphragm 46. A flexible cup 52, which is shaped just like a suction cup, in other words in annular and somewhat conically shaped, is fitted over a protruding neck on the retainer cap 47. The flexible cup itself has a center retainer neck 53 that passes through an opening in the neck of the retainer cap. The

center neck 53 has a control pressure passageway 54 defined therein. This control pressure passageway opens into the chamber 55, which is a control pressure chamber, defined by .the cap .47. The flexible cup 52 forms a flexible or resilient sealing member on the will engage the inner surface of the neck on the retainer cap and hold the sealing suction type cup 52 in place.

a 4 The diaphragm-46 is provided with aisrnall "frustoconical interior'sealing chamber 57 defined in'the center thereof and which-is open throughan opening aligned with the passageway 44. The small 'frusto-coni-' 'cal chamber 57 forms an annular thin lip 57A that seals against the surface of the block 42 around the I passageway 44. The annular lip member 57A is very thin around its edges, and, being elastomeric and flexible, will flex or bend to accommodate'the local irregularities around the passageway 44.

A pilot pressure or sensing passageway 60 is openpredetermineddistance' from the wall 13 so that when the valve 11' is locked on the lugs' 35',the outer peripheral edges of thesealing cup 52 for control-pressure to the valvesurrounds the opening 20 fromthe control pressure chamber for that particular valve, and seals so that the control pressure will not leak 'out aroundthe peripheral edges of the cup 52. The control pressure is suppliedto chamber 55 through the cup 52 I The operation of the valve 11 is by pressure dif- I ferentials, and-there are actually no pivoting mechanically moving parts. In normal operation, the pressure in the plenum chamber 15 will be approximatelyZ pounds per square inch higher than atmospheric pressure.

When there is no levitated vehicle above the valve, the pressure at nozzle 31 will be lower than the pressure at the passage end 40. Assuming automatic operation, the pressure inside the chamber 55 will be substantially the same as that in pressure pilot conduit 60 (at atmospheric). The spring 48 will provide a sufficient resilient bias to push the diaphragm 46 up against the block 42 and the lips 57A will seal around the bottom edge of the opening 44. Pressure from the plenum chamber 15 will communicate with the passageway 44 through passageway 45 causing duct pressure on the inside of the frusto-conical opening 57 and forcing the lip edges 57A against the surface of the block around the passageway 44.

The fluid pressure acting through passageway 45 and passageway 44 will act on the bottom side of the diaphragm 41 and because of the lower pressure in nozzle 31 will force it'upwardly as shown in FIG. 3. The differential in pressure will cause the sealing of the diaphragm 41 against the opposite side or upper side surfaces of the passageway 40. This will preventair or to the opposite side of the fluid under pressure from escaping out through the nozzle 31. It should be noted that the sealing surface shown at 62 is a planar surface extending across the valve, and that the diaphragm 41 billows up as shown in dotted lines in FIG. 5 for the sealing position. The surface of the diaphragm 41 that defines part of passageway 40 seals all the way across the passageway 40. The nozzle 31 extends only part way across surface 62, so there is a sealing against surface 62 around the entrance to the nozzle 31 and the flow of fluid is shut off completely. Note also that the surface 43 of block 42 is depressed in the center portion to enlarge the effective area of passageway 40 when the diaphragm is in open condition.

Assuming that the levitated vehicle, having the seal 27, is along in automatic operation, there will be fluid pressure under the vehicle which is higher than atmospheric pressure. The fluid pressure for levitation is present in chamber 63 defined by seal 27. As the vehicle moves along, the edge of chamber 63 .will overlie the pilot passageway 60. There will then be a pressure rise in the passageway 60, and thus in the recess 61. This higher than atmospheric pressure, which probably is about half of the pressure in plenum chamber 15, or about 1 pound per square inch above atmospheric, acts on the upper surface of the diaphragm 46. This pressure area is sufficiently large to move the diaphragm 46 away from the bottom surface of block 42 and overcomes the force of spring 48. The diaphragm 46 will move downwardly, and actually snap the sealing lips 57A away from the passageway 44. This will then open a pressure bleed path from under diaphragm 41 through the passageways 44, 61 and 60 to a lower pressure under the levitated vehicle. Because the passageway 45 is much smaller in cross sectional size than the other passageways the diaphragm 41 will quickly collapse, and open communication between the passageway 40 and the nozzle 31. The passageway 45 is always open to passageway 44, but passageway 45 is restricted to limit the quantity of flow through it.

Fluid from plenum chamber will then flow out underneath the vehicle and will continue to levitate the vehicle until the pilot passageway 60 is again uncovered. It should be noted that because the passageway 45 is much smaller in size than the passageways 44, 60 and 61, the amount of fluid flowing through passageway 45 and out through passageway 61 is not great and will not cause any unwanted build up in pressure under diaphragm 41. The flow of fluid out nozzle 31 will continue until the port 60 again is in a region of pressure sufficiently low in relation to the control pressure in chamber 55 so the spring 48 is effective to move diaphragm 46 up to position against the sealing surfaces around passageway 44 so that the lips 57A will seal around the passageway 44. Pressure from duct 15 acting through passageway 45 and the upper part of passageway 44 will then force the diaphragm 41 to its closed position to shut off the flow of fluid out nozzle The reverse flow of fluid from under diaphragm 41 when the valve first opens causes a puff of air to be blown back out through the pilot passageway 60. There is also some flow out passageway 60 all the while the valve is open because of the communication of passageway 45 with the plenum chamber.

The reverse puff of air out through the pilot passageway insures that it will be cleaned out each time if any dirt or foreign material comes into the pilot passageway, and the valve operation is fairly silent, free of moving mechanical parts, and very reliable.

If desired, different than atmospheric control pressures can be applied through separate'control pressure chambers 17B in headers 17 and leading to each valve from conduits 21 and 22. The operation just described is when the conduit 21, for example, is at atmospheric pressure and is open to the control pressure chamber for the valve being actuated. If a higher than atmospheric control pressure is utilized through the opening 20, the valve will remain closed even though there is a levitated vehicle above it. The control pressure higher than atmospheric acting against the underside of the diaphragm 46 can be used to offset the pilot pressure through the valve 61. Also, a partial vacuum (lower than atmospheric pressure) canbe supplied to the header andcontrol pressure chamber 55 for a valve to open the valve at a time when there is no vehicle above the valve itself. The control pressure differential on control diaphragm 46 necessary to open the valve has to be sufficiently high to overcome the very light spring force. One psi is ample, and fractions of a pound per square inch also will work. The spring force on the control diaphragm is extremely light. By controlling the pressures in the control chamber 55 valve actuation can be automatic for levitated vehicles if desired, or can be in response to predetermined pressure signals.

The control chambers 17B for each valve also permit opening the valves for initial starting of a'levitated vehicle by supplying a vacuum to the control pressure chambers while fluid pressure is in the plenum chamber. This will cause the valves to open and air to go out through the nozzles 31 of the valves so controlled. This then will lift the vehicle and by then returning the control pressure to atmospheric the unit will operate automatically. Vehicle speed can also be the-control pressure in chamber 55 is sufficiently highto prevent diaphragm 46 from moving away from block 42.

It should be noted that several valves will be controlled by the pressure in conduit 21 and several valves will be controlled by conduit 22. These valves are interspersed along the track and opening of different groups of valves at different pressures permits control of vehicle spacing'or speed if desired. 4

What is claimed is:

1. In combination, a valve assembly having a main valve means for controlling flow of fluid between two fluid pressure areas, control means responsive to fluid pressure differentials for controlling movement of said main valve means, a support member having a first surface, said valve means controlling fluid flow to a location open to said first surface, pressure header means spaced from said first surface, said pressure header means having an opening therein, said control means for controlling operation of said valve means including a fluid pressure responsive device, a control pressure passageway open to said fluid pressure responsive device, means to releasably lock said valve assembly with respect to said support member so a portion of said valve assembly is properly positioned with respect to said first surface, and resilient sealing means forming a portion of a control pressure passageway, said conically shaped wall extending outwardly to greater diameter in direction away from the valve assembly,

the outer peripheral edge portion of said wallengaging and sealing on said pressure header. 7 3. The combination as specified in claim 1 wherein said valve means is actuated by fluid pressure and said fluid pressure responsive devicecomprises a movable diaphragm controlling fluid flow to actuate saidvalve in response to pressure in said control pressure passageway acting on said movable diaphragm.

' .4. The combination asspecified in claim 3 and separate bias means biasing said diaphragm to a first normal position. Y 8

5. In combination, a valve assembly having a main valve means for controlling flow of fluid between two fluid pressure areas, control means responsive to fluid pressure differentials for controlling movement of said having an opening defined therein, said control meansmain valve means, a support member having a first surface, said valve means controlling-fluid flow to a loca tionopen to said first surface, a control conduit spaced from said first surface, said control conduit carrying fluid at control pressure levels, said control conduit for controlling operation of said valve means including a fluid pressure responsive device, passageway open to said fluid pressure responsive device,-m eans to releasably lock said valve assembly with respect to said support member so a portion of said valve assembly is positioned at a desired location with respect to said first surface, and resilient sealing means forming a portion of. said control passageway,

and sealingly surrounding said" opening in said control conduit when said valve assembly is. releasably locked with respect to said support member, and permitting separation of the valve assembly from the'control-'conduit when the releasable lock means is released.

6. The combination as specified in claim 5 wherein said resilient sealing means comprises a flexible cup means attached to said valve assembly, said cup having a generally conical wall extending outwardly from a central axis in direction away from said valve assembly,

the outer peripheral edge portion of said wall engaging and sealing on said control conduit whenthe valve assembly is releasably locked with respect to said support member. v

a: p -=r a control 

1. In combination, a valve assembly having a main valve means for controlling flow of fluid between two fluid pressure areas, control means responsive to fluid pressure differentials for controlling movement of said main valve means, a support member having a first surface, said valve means controlling fluid flow to a location open to said first surface, pressure header means spaced from said first surface, said pressure header means having an opening therein, said control means for controlling operation of said valve means including a fluid pressure responsive device, a control pressure passageway open to said fluid pressure responsive device, means to releasably lock said valve assembly with respect to said support member so a portion of said valve assembly is properly positioned with respect to said first surface, and resilient sealing means forming a portion of a control pressure passageway, said resilient sealing means sealing around said opening in said pressure header means when said valve assembly is properly positioned with respect to said support member and permitting separation of the valve assembly from the pressure header means when the releasable lock means is released.
 2. The combination as specified in claim 1 wherein said resilient sealing means comprises a flexible cup attached to said valve assembly and having a generally conically shaped wall extending outwardly to greater diameter in direction away from the valve assembly, the outer peripheral edge portion of said wall engaging and sealing on said pressure header.
 3. The combination as specified in claim 1 wherein said valve means is actuated by fluid pressure and said fluid pressure responsive device comprises a movable diaphragm controlling fluid flow to actuate said valve in response to pressure in said control pressure passageway acting on said movable diaphragm.
 4. The combination as specified in claim 3 and separate bias means biasing said diaphragm to a first normal position.
 5. In combination, a valve assembly having a main valve means for controlling flow of fluid between two fluid pressure areas, control means responsive to fluid pressure differentials for controlling movement of said main valve means, a support member having a first surface, said valve means controlling fluid flow to a location open to said first surface, a control conduit spaced from said first surface, said control conduit carrying fluid at control pressure levels, said control conduit having an opening defined therein, said control means for controlling operation of said valve means including a fluid pressure responsive device, a control passageway open to said fluid pressure responsive device, means to releasably lock said valve assembly with respect to said support member so a portion of said valve assembly is positioned at a desired location with respect to said first surface, and resilient sealing means forming a portion of said control passageway, and sealingly surrounding said opening in said control conduit when said valve assembly is releasably locked with respect to said support member, and permitting separation of the valve assembly from the control conduit when the releasable lock means is released.
 6. The combination as specified in claim 5 wherein said resilient sealing means comprises a flexible cup means attached to said valve assembly, said cup having a generally conical wall extending outwardly from a central axis in direction away from said valve assembly, the outer peripheral edge portion of said wall engaging and sealing on said control conduit when the valve assembly is releasably locked with respect to said Support member. 